Double-acting gas engine with slot scavenging



Sept. 23, 1930. w. RIEHM 1,776,665 DOUBLE ACTING GAS ENGINE WITH SLOT SCAVENGING Filed. May 25. 1928 a, 7 .II *7 mama Sept. 23, .1930

UNITED srAras v;1,71t,ass

PATENT OFFICE wrnnnmu mania, or Auesnune, GERMANY, assrenon 'ro ran r1311 monnmn- FABRIK anesnunelnunnnanne, axrrnnensnnnscnarr, or auesnnae, ear-rm,

A CORPORATION OF GERMANY nounnn-acrrne ens ENGINE wrrn SLOT soavnneme Application flled Hay 25, 1928, Serial No. 280,555, and in Germany June 18, :14

This invention relates to internal-combustion engines and more particularly to twostr ke cycle engines.

' One object of the invention is the provision, in a two-stroke cycle engine having a piston controlled exhaust valve and having slotted fuel-inlet and scavenging airports,-

of an additional exhaust controllin means.

Other objects and advantages 0 the in- 1o vention will be apparent from the following description and from the accompanying drawings in' which The drawing is a longitudinal sectional view through the cylinder of a double-acting: two-stroke cycle engine constructed in accordance with this "invention.

This invention is preferably employed in connection with a two-stroke cycle engine adapted to operate upon an explosive mixzo hire, a double-acting engine being illustrated in the drawing. 1 For purposes of easier description, the figure of the drawing is somewhat diagrammatic in fcharacter and onlyone-half of a double-acting engineis shown, it being understood that the remaining half is similar in construction to that illustrated.

As shown, the engine cylinder ,6 which may be supplied with means such as spark o plug it, for causing the ignition of the compressed fuel mixture, is provided with exhaust ports or slots d throu h which the burnt gases travel from the com ustion chamber. Scavenging air ports or slots a are rospaced away from the exhaust ports. The cylinder walls are also provided with fuel inlet (ports or slots'c, arranged in a plane space from the scavenging air ports a. 0 erating within the cylinder is a piston which is adapted to open and close the various ports. The ports a, c andd are arranged; as shown,

at one side of the cylinder 6 so that the scavenging air entering the cylinder may flow alon the concave u per side of the piston, and a dug the cylind r wall opposite the inlet slots toward the top of the cylinder,

It then reverses as it flows over the curved top of the cylinder and flows toward the exhaust slots d, pushing the exhaust gases ahead forced through theexhaust slots (1' by the invided in the cylinder walls and in a .p ane of it. The charge mixture follbws the path of the scavenging air, this charge mixture comprising a mixture of fresh gas introduced through t e inlet slots 0 and air introduced through the air slots-a. Proceeding ahead of the charge mixture there is therefdre a stratum of clean scavenging'air, which provents mixing of the charge mixture and the exhaust gases. This air stratum, indicated at c in the drawing, reaches the exhaust slots (1 ahead of the charge mixture which is indicated by the crossed lines.

To prevent the loss and waste of scaven'ging air and also the loss and waste of combustible mixture which might otherwise be coming stream as well as by the forwardly moving piston even after the fuel inlet slots close, the entire exhaust is controlled b a means 9 independently of the piston. his 7 means g referably comprises a quick closconnected to the piston so as to rotate in timed v relation with thepiston operation so that the passage f will be closed every second stroke of. the piston while the clean air stratum e is escapin from the d and before the fresh fue mixture reaches these exhaust slots.- In this manner the escape 'of the fuel mixture is prevented, and the exhaust of the gases from the cylinder is controlled to obtain themaximum economy of both fuel and scavenging air. v a

Whilethe form of ap aratus herein described constitutes a pre erred embodiment ofthe invention, it is to beunde' :tood that the invention is not limited to this precise form of apparatus, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims,

What is claimed is: I

1. A two-stroke cycle engine comprising a' -cylinder having an exhaust port, a iston in said cylinder adapted to open and c ose said port, separate piston controlled scavengin and fuel inlet ports in said cylinder, sai

scavenging air port is opened just before the fuel inlet port is opened to provide a small stratum merely of scavenging air between the'fuel mixture and the exhaust gases during scavenging, and a valve for controlling the escape of the exhaust gases from said e scavenging air stratum escapes from the cylinder p 2. A two-stroke cycle engine of the character described comprising a cylinder having an exhaust port, a scavenging air port and a fuel inlet port in the wall thereof and at the same side of the cylinder to provide for reverse scavenging flow, a piston operating ,within said cylinder to control said ports successively so that the exhaust port is first opened and then the scavenging air ports are opened just before the gas inlet orts to provide a scavenging air stratum burnt gases and the new mixture charge, and a valve for controlling the exhaust from said cylinder to close the exhaust passa e while t e scavenging air stratum escapes rom the cylinder.

In testimony whereof I have aflixed my signature.

WILHELM RIEI-IM.

cylinder to close the exhaust passage while t etween the 

